# Lesson 4

Measure and Estimate in Centimeters

### Lesson Purpose

The purpose of this lesson is for students to estimate and measure lengths in centimeters. Students use a ruler for the first time.

### Lesson Narrative

In previous lessons, students measured lengths in centimeters with physical units and the rulers they constructed.

The purpose of this lesson is to build on their experiences with centimeters to estimate lengths in centimeters and measure lengths with a centimeter ruler. In Activity 1, students estimate the length of objects in the classroom. Objects have been suggested, but they can be changed based on what is available in the classroom. Most of the objects students use to estimate and measure length for the purposes of this lesson should be 530 cm long. At least one object should be between 5090 cm long to give students the opportunity to estimate longer objects and an opportunity to experience the need to iterate a ruler to find a longer measurement in anticipation of future lessons. In Activity 2, students measure the actual length of the objects.

• Action and Expression
• MLR2

### Learning Goals

Teacher Facing

• Estimate lengths in centimeters.
• Use standard rulers to measure length in centimeters.

### Student Facing

• Let’s estimate and measure in centimeters.

### Required Materials

Materials to Gather

### Required Preparation

Activity 1:

• Each group of 2 needs access to several objects between 530 cm long and at least one object between 5090 cm long.

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

Reflect on how you can reinforce the work done in today’s lesson outside of math class. When can you ask students questions involving the estimation work done today? Are there opportunities at other times during the day to ask students to estimate the lengths of objects?